"The United States currently relies heavily on coal, oil, and
natural gas for its energy. Fossil fuels are nonrenewable, that
is, they draw on finite resources that will eventually dwindle,
becoming too expensive or too environmentally damaging to
retrieve. In contrast, renewable energy resources such as wind and
solar energy are constantly replenished and will never run out."
[quote from the National Renewable Energy Laboratory]
One of the most powerful sources of renewable energy comes from the sun. The sun produces an enormous amount of energy. In fact more energy from the sun falls on the earth in just one hour than is used by the entire world’s population in an entire year! Scientists have developed a number of different technologies that harness this energy for our use.
One of the most effective uses of these technologies is solar photovoltaics. This technology uses solar cells to convert sunlight directly into electricity. Solar cells are generally made from silicon and when combined into modules with around 40 cells each, are referred to as solar panels. Powering a typical home uses around 10 to 20 solar panels. These panels are either mounted at an angle facing south, or on a tracking device that follows the sun throughout the day.
While installation of solar panels can seem a little pricey (an average sized system will cost $15,000 to $29,000 to install) there are many federal, state, and local incentives available to push prices down. The cost of solar panels and installation is also coming down, while traditional utility companies continue to increase their rates. Finally, once solar panels are installed, they lower a household’s electric bill by a considerable amount.
Wind energy has been utilized for hundreds of years. The modern day equivalent of a windmill is called a wind turbine. Wind turbines are mounted on a tower and use the wind to spin their propeller-like blades which are mounted on a shaft with 2 to 3 blades, forming a rotor. As the rotor spins, it spins a generator which then produces electricity. Most often, a large number of wind turbines are built close together and form a wind plant.
Today many electric companies use wind plants to supply energy to their customers. Stand-alone wind turbines are less common, but can be used in windy areas by individual homeowners or farmers to bring down electric bills. Since wind energy has no fuel costs, electric companies using this resource are able to charge lower, fixed rates, with contracts locking in these rates lasting up to 30 years.
The concept of bioenergy is not a new idea. Bioenergy refers to the use of organic matter taken from plants to create energy. One source of organic matter that has been used throughout history to produce bioenergy is wood. Wood was traditionally used to cook food and produce heat, and is still the largest biomass energy resource used today. Other common sources we now use include food crops, grassy plants, residues from forestry or agriculture, and even certain types of algae.
The greatest benefit of using biomass is that it can be used for fuel in products that would otherwise use fossil fuels. Because of this, biomass energy has the potential to greatly reduce greenhouse gas emissions. The price of producing and using fuels developed using biomass continues to lower as research into new technologies results in greater production efficiency.
Geothermal energy refers to heat that comes from the earth. While air temperatures in some climates can vary greatly depending on the time of year, the temperature below ground stays fairly constant throughout the year. The shallow ground which is near to the earth’s surface maintains a temperature of 50° to 60° F. The energy from this consistent heat is harnessed using geothermal systems built underground. These systems can be both small and large scale.
Geothermal systems most commonly provide heating and cooling for buildings and homes. To do this, the system pulls the heat from the ground and distributes it through air ducts as warm air to warm the inside of a building. In order to cool a building the process is reversed- heat is extracted from the air inside and either moved back into the earth or used to heat the building’s water tank.
While initial installation prices of geothermal systems can seem high, the cost of running and maintaining them is much lower than traditional fuel burning systems. The government also provides a 30% tax credit on the total cost of installation, making the initial bill lower as well.